SSH Key: “Permissions 0644 for 'id_rsa.pub' are too open.” on mac

Question

I generate a ssh key pair on my mac and add the public key to my ubuntu server(in fact, it is a virtual machine on my mac),but when I try to login the ubuntu server,it says:

Answer 1

In my case, it was a .pem file. Turns out holds good for that too. Changed permissions of the file and it worked.

chmod 400 ~/.ssh/dev-shared.pem

Thanks for all of those who helped above.